Biblio

Found 879 results
Journal Article
Authors: Zhu Hui, Gu Wenyao, and Chen Lunjin
Title: Statistical analysis on plasmatrough exohiss waves from the Van Allen Probes
Abstract: In this study using Van Allen Probe wave observations we investigate the statistical properties of exohiss waves, which are structureless whistler mode waves observed outside the plasmapause. The exohiss waves are identified based on the cold electron number density, frequency distribution, ellipticity, and wave normal angle. The statistical analysis on exohiss wave properties shows that exohiss waves prefer to occur over 3Date: 06/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026359 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026359
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Authors: Shen Xiao‐Chen, Li Wen, Ma Qianli, Agapitov Oleksiy, and Nishimura Yukitoshi
Title: Statistical Analysis of Transverse Size of Lower Band Chorus Waves Using Simultaneous Multisatellite Observations
Abstract: Chorus waves are known to accelerate or scatter energetic electrons via quasi‐linear or nonlinear wave‐particle interactions in the Earth's magnetosphere. In this letter, by taking advantage of simultaneous observations of chorus waveforms from at least a pair of probes among Van Allen Probes and/or Time History of Events and Macroscale Interactions during Substorms (THEMIS) missions, we statistically calculate the transverse size of lower band chorus wave elements. The average size of lower band chorus wave element is found to be ~315±32 km over L shells of ~5–6. Furthermore, our results suggest that the scale size of lower band chorus tends to be (1) larger at higher L shells; (2) larger at higher magnetic latitudes, especially on the dayside; and (3) larger in the azimuthal direc. . .
Date: 05/2019 Publisher: Geophysical Research Letters DOI: 10.1029/2019GL083118 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083118
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Authors: Meredith Nigel P
Title: Statistical analysis of relativistic electron energies for cyclotron resonance with EMIC waves observed on CRRES
Abstract: Electromagnetic ion cyclotron (EMIC) waves which propagate at frequencies below the proton gyrofrequency can undergo cyclotron resonant interactions with relativistic electrons in the outer radiation belt and cause pitch-angle scattering and electron loss to the atmosphere. Typical storm-time wave amplitudes of 1–10 nT cause strong diffusion scattering which may lead to significant relativistic electron loss at energies above the minimum energy for resonance, Emin. A statistical analysis of over 800 EMIC wave events observed on the CRRES spacecraft is performed to establish whether scattering can occur at geophysically interesting energies (≤2 MeV). While Emin is well above 2 MeV for the majority of these events, it can fall below 2 MeV in localized regions of high plasma density and/o. . .
Date: 06/2003 Publisher: Journal of Geophysical Research DOI: 10.1029/2002JA009700 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2002JA009700/full
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Authors: Kim Kyung‐Chan, and Shprits Yuri
Title: Statistical Analysis of Hiss Waves in Plasmaspheric Plumes Using Van Allen Probe Observations
Abstract: Plasmaspheric hiss waves commonly observed in high‐density regions in the Earth's magnetosphere are known to be one of the main contributors to the loss of radiation belt electrons. There has been a lot of effort to investigate the distributions of hiss waves in the plasmasphere, while relatively little attention has been given to those in the plasmaspheric plume. In this study, we present for the first time a statistical analysis of the occurrence and the spatial distribution of wave amplitudes and wave normal angles for hiss waves in plumes using Van Allen Probes observations during the period of October 2012 to December 2016. Statistical results show that a wide range of hiss wave amplitudes in plumes from a few picotesla to >100 pT is observed, but a modest (<20 pT) wave amplitude is. . .
Date: 03/2019 Publisher: Journal of Geophysical Research: Space Physics Pages: 1904 - 1915 DOI: 10.1029/2018JA026458 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026458
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Authors: Spasojevic M.
Title: Statistical analysis of ground-based chorus observations during geomagnetic storms
Abstract: Chorus observations from two ground-based, Antarctic receiving stations are analyzed for a set of geomagnetic storms from 2000 to 2010. Superposed epoch analysis is performed together with statistical hypothesis testing to determine whether the observed quantities (geomagnetic indices, outer belt energetic electron fluxes, and chorus properties) are statistically significantly different as functions of storm phase, storm size, and storm type. Waves generated in the outer dayside magnetosphere and observed on the ground at South Pole Station are suppressed during main phase and are statistically unchanged from random intervals during recovery phase. Waves generated in the inner magnetosphere and observed on the ground at Palmer Station are significantly enhanced during storm main phase and . . .
Date: 10/2014 Publisher: Journal of Geophysical Research: Space Physics Pages: 8299 - 8317 DOI: 10.1002/jgra.v119.1010.1002/2014JA019975 Available at: http://doi.wiley.com/10.1002/jgra.v119.10http://doi.wiley.com/10.1002/2014JA019975
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Authors: Boynton R. J., Balikhin M. A., and Mourenas D.
Title: Statistical analysis of electron lifetimes at GEO: Comparisons with chorus-driven losses
Abstract: The population of electrons in the Earth's outer radiation belt increases when the magnetosphere is exposed to high-speed streams of solar wind, coronal mass ejections, magnetic clouds, or other disturbances. After this increase, the number of electrons decays back to approximately the initial population. This study statistically analyzes the lifetimes of the electron at Geostationary Earth Orbit (GEO) from Los Alamos National Laboratory electron flux data. The decay rate of the electron fluxes are calculated for 14 energies ranging from 24 keV to 3.5 MeV to identify a relationship between the lifetime and energy of the electrons. The statistical data show that electron lifetimes increase with energy. Also, the statistical results show a good agreement up to ∼1 MeV with an analytical mod. . .
Date: 08/2014 Publisher: Journal of Geophysical Research: Space Physics Pages: 6356 - 6366 DOI: 10.1002/2014JA019920 Available at: http://doi.wiley.com/10.1002/2014JA019920
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Authors: Artemyev A. V., Mourenas D., Agapitov O. V., Vainchtein D. L., Mozer F S, et al.
Title: Stability of relativistic electron trapping by strong whistler or electromagnetic ion cyclotron waves
Abstract: In the present paper, we investigate the trapping of relativistic electrons by intense whistler-mode waves or electromagnetic ion cyclotron waves in the Earth's radiation belts. We consider the non-resonant impact of additional, lower amplitude magnetic field fluctuations on the stability of electron trapping. We show that such additional non-resonant fluctuations can break the adiabatic invariant corresponding to trapped electron oscillations in the effective wave potential. This destruction results in a diffusive escape of electrons from the trapped regime of motion and thus can lead to a significant reduction of the efficiency of electron acceleration. We demonstrate that when energetic electrons are trapped by intense parallel or very oblique whistler-mode waves, non-resonant magnetic . . .
Date: 08/2015 Publisher: Physics of Plasmas Pages: 082901 DOI: 10.1063/1.4927774 Available at: http://scitation.aip.org/content/aip/journal/pop/22/8/10.1063/1.4927774
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Authors: Khazanov K. G. V., Sibeck D. G., Tel'nikhin A. A., and Kronberg T. K.
Title: Spectra of keV protons related to ion-cyclotron wave packets
Abstract: We use the Fokker-Planck-Kolmogorov equation to study the statistical aspects of stochastic dynamics of the radiation belt (RB) protons driven by nonlinear electromagnetic ion-cyclotron (EMIC) wave packets. We obtain the spectra of keV protons scattered by these waves that show steeping near the gyroresonance, the signature of resonant wave-particle interaction that cannot be described by a simple power law. The most likely mechanism for proton precipitation events in RBs is shown to be nonlinear wave-particle interaction, namely, the scattering of RB protons into the loss cone by EMIC waves.
Date: 01/2017 Publisher: Physics of Plasmas DOI: http://dx.doi.org/10.1063/1.4973323 Available at: http://http://aip.scitation.org/doi/abs/10.1063/1.4973323
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Authors: Gkioulidou Matina, Ohtani S, Mitchell D G, Ukhorskiy A., Reeves G D, et al.
Title: Spatial structure and temporal evolution of energetic particle injections in the inner magnetosphere during the 14 July 2013 substorm event.
Abstract: Recent results by the Van Allen Probes mission showed that the occurrence of energetic ion injections inside geosynchronous orbit could be very frequent throughout the main phase of a geomagnetic storm. Understanding, therefore, the formation and evolution of energetic particle injections is critical in order to quantify their effect in the inner magnetosphere. We present a case study of a substorm event that occurred during a weak storm (Dst ~ - 40 nT) on 14 July 2013. Van Allen Probe B, inside geosynchronous orbit, observed two energetic proton injections within ten minutes, with different dipolarization signatures and duration. The first one is a dispersionless, short timescale injection pulse accompanied by a sharp dipolarization signature, while the second one is a dispersed, longer t. . .
Date: 02/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020872 Available at: http://doi.wiley.com/10.1002/2014JA020872
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Authors: Anderson B. R., Shekhar S., Millan R M, Crew A. B., Spence H E, et al.
Title: Spatial Scale and Duration of One Microburst Region on 13 August 2015
Abstract: Prior studies of microburst precipitation have largely relied on estimates of the spatial scale and temporal duration of the microburst region in order to determine the radiation belt loss rate of relativistic electrons. These estimates have often relied on the statistical distribution of microburst events. However, few studies have directly observed the spatial and temporal evolution of a single microburst event. In this study, we combine BARREL balloon-borne X-ray measurements with FIREBIRD-II and AeroCube-6 CubeSat electron measurements to determine the spatial and temporal evolution of a microburst region in the morning MLT sector on 13 August 2015. The microburst region is found to extend across at least four hours in local time in the morning sector, from 09:00 to 13:00 MLT, and from. . .
Date: 04/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023752 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023752/full
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Authors: Mann I. R., Usanova M. E., Murphy K., Robertson M. T., Milling D. K., et al.
Title: Spatial localization and ducting of EMIC waves: Van Allen Probes and ground-based observations
Abstract: On 11 October 2012, during the recovery phase of a moderate geomagnetic storm, an extended interval (> 18 h) of continuous electromagnetic ion cyclotron (EMIC) waves was observed by Canadian Array for Real-time Investigations of Magnetic Activity and Solar-Terrestrial Environment Program induction coil magnetometers in North America. At around 14:15 UT, both Van Allen Probes B and A (65° magnetic longitude apart) in conjunction with the ground array observed very narrow (ΔL ~ 0.1–0.4) left-hand polarized EMIC emission confined to regions of mass density gradients at the outer edge of the plasmasphere at L ~ 4. EMIC waves were seen with complex polarization patterns on the ground, in good agreement with model results from Woodroffe and Lysak (2012) and consistent with Earth's . . .
Date: 02/2014 Publisher: Geophysical Research Letters Pages: 785 - 792 DOI: 10.1002/2013GL058581 Available at: http://doi.wiley.com/10.1002/2013GL058581
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Authors: Ohtani S, Motoba T., Gkioulidou M., Takahashi K., and Singer H J
Title: Spatial Development of the Dipolarization Region in the Inner Magnetosphere
Abstract: The present study examines dipolarization events observed by the Van Allen Probes within 5.8 RE from Earth. It is found that the probability of occurrence is significantly higher in the dusk‐to‐midnight sector than in the midnight‐to‐dawn sector, and it deceases sharply earthward. A comparison with observations made at nearby satellites shows that dipolarization signatures are often highly correlated (c.c. > 0.8) within 1 hr in MLT and 1 RE in RXY, and the dipolarization region expands earthward and westward in the dusk‐to‐midnight sector. The westward expansion velocity is estimated at 0.4 hr (in MLT) per minute, or 60 km/s, which is consistent with the previously reported result for geosynchronous dipolarization. The earthward expansion is apparently less systematic than the . . .
Date: 06/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025443 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025443
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Authors: Cho J.-H., Lee D.-Y., Noh S.-J., Kim H., Choi C. R., et al.
Title: Spatial dependence of electromagnetic ion cyclotron waves triggered by solar wind dynamic pressure enhancements
Abstract: In this paper, using the multisatellite (the Van Allen Probes and two GOES satellites) observations in the inner magnetosphere, we examine two electromagnetic ion cyclotron (EMIC) wave events that are triggered by Pdyn enhancements under prolonged northward interplanetary magnetic field quiet time preconditions. For both events, the impact of enhanced Pdyn causes EMIC waves at multiple points. However, we find a strong spatial dependence that EMIC waves due to enhanced Pdyn impact can occur at multiple points (likely globally but not necessarily everywhere) but with different wave properties. For Event 1, three satellites situated at a nearly same dawnside zone but at slightly different L shells see occurrence of EMIC waves but in different frequencies relative to local ion gyrofrequencies. . .
Date: 05/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023827 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023827/full
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Authors: Sarno-Smith Lois K., Larsen Brian A., Skoug Ruth M., Liemohn Michael W., Breneman Aaron, et al.
Title: Spacecraft surface charging within geosynchronous orbit observed by the Van Allen Probes
Abstract: Using the Helium Oxygen Proton Electron (HOPE) and Electric Field and Waves (EFW) instruments from the Van Allen Probes, we explored the relationship between electron energy fluxes in the eV and keV ranges and spacecraft surface charging. We present statistical results on spacecraft charging within geosynchronous orbit by L and MLT. An algorithm to extract the H+ charging line in the HOPE instrument data was developed to better explore intense charging events. Also, this study explored how spacecraft potential relates to electron number density, electron pressure, electron temperature, thermal electron current, and low-energy ion density between 1 and 210 eV. It is demonstrated that it is imperative to use both EFW potential measurements and the HOPE instrument ion charging line for examin. . .
Date: 02/2016 Publisher: Space Weather Pages: n/a - n/a DOI: 10.1002/2015SW001345 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2015SW001345/full
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Authors: Lesley Mellinee
Title: “Spacecraft Reveals Recent Geological Activity on the Moon”
Abstract: Through a content analysis of 200 “tweets,” this study was an exploration into the distinct features of text posted to NASA's Twitter site and the potential for these posts to serve as more engaging scientific text than traditional textbooks for adolescents. Results of the content analysis indicated the tweets and linked texts on the NASA Twitter site were constructed primarily as a form of “adapted primary literature” where science texts created by scientists for other scientists are presented in a slightly modified format for the general public. Further, the content analysis revealed the majority of text posted was designed to cultivate scientific knowledge for novices. Findings of the content analysis are presented and implications for teaching scientific literacies to adolescen. . .
Date: 02/2014 Publisher: Journal of Adolescent & Adult Literacy Pages: 377 - 385 DOI: 10.1002/jaal.2014.57.issue-510.1002/jaal.258 Available at: http://doi.wiley.com/10.1002/jaal.2014.57.issue-5http://doi.wiley.com/10.1002/jaal.258
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Authors: Lanzerotti Louis J., and Baker Daniel N
Title: Space Weather Research: Earth's Radiation Belts
Abstract: Fundamental research on Earth's space radiation environment is essential for the design and the operations of modern technologies – for communications, weather, navigation, national security – that fly in the hostile space weather conditions above Earth's atmosphere. As the technologies become ever more advanced, more sophisticated understanding – and even predictability – of the environment is required for mission success
Date: 05/2017 Publisher: Space Weather DOI: 10.1002/2017SW001654 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017SW001654/full
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Authors: Lee Jongkil, Kim Kyung-Chan, Giuseppe Romeo, Ukhorskiy Sasha, Sibeck David, et al.
Title: Space Weather Operation at KASI with Van Allen Probes Beacon Signals
Abstract: The Van Allen Probes (VAPs) are the only modern NASA spacecraft broadcasting real-time data on the Earth's radiation belts for space weather operations. Since 2012, the Korea Astronomy and Space Science Institute (KASI) has contributed to the receipt of this data via a 7-m satellite tracking antenna and used these data for space weather operations. An approximately 15-min period is required from measurement to acquisition of Level-1 data. In this paper, we demonstrate the use of VAP data for monitoring space weather conditions at geostationary orbit (GEO) by highlighting the Saint Patrick's Day storm of 2015. During that storm, Probe-A observed a significant increase in the relativistic electron flux at 3 RE. Those electrons diffused outward resulting in a large increase of the electron fl. . .
Date: 01/2018 Publisher: Space Weather DOI: 10.1002/2017SW001726 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017SW001726/full
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Authors: Turner Drew L
Title: Space science: Near-Earth space shows its stripes
Abstract: Using some of the first scientific satellites put into orbit during the late 1950s, teams led by physicists James Van Allen in the United States and Sergei Vernov in the Soviet Union independently reported1, 2 on defined regions of radiation in near-Earth space. These regions came to be known as Earth's radiation belts, and they represent the first major scientific discovery of the space age. However, despite decades of study, many questions in radiation-belt physics remain unanswered, mostly concerning the nature of the inner and outer belts, which are populated by electrons moving at near the speed of light. As society becomes ever more dependent on satellite-based technology, it is increasingly important to understand the variability in the radiation belts, because the highest-energy . . .
Date: 03/2014 Publisher: Nature Pages: 308 - 309 DOI: 10.1038/507308a Available at: http://www.nature.com/doifinder/10.1038/507308a
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Authors: Lanzerotti Louis J.
Title: Space Research and Space Weather: Some Personal Vignettes 1965 to Early 1980s
Abstract: Personal vignettes are given on early days of space research, space weather, and space advisory activities from 1965 to early 1980s.
Date: 04/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA026763 Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JA026763
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Authors: Hudson M K
Title: Space physics: A fast lane in the magnetosphere
Abstract: A marriage between satellite observations and modelling has shown that acceleration of electrons in the magnetosphere can be explained by scattering of these particles by plasma oscillations known as chorus waves.
Date: 12/2013 Publisher: Nature Pages: 383 - 384 DOI: 10.1038/504383a Available at: http://www.nature.com/doifinder/10.1038/504383a
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Authors: Wang Chih-Ping, Xing Xiaoyan, Nakamura T. K. M., Lyons Larry R., and Angelopoulos Vassilis
Title: Source and structure of bursty hot electron enhancements in the tail magnetosheath: Simultaneous two-probe observation by ARTEMIS
Abstract: Bursty enhancements of hot electrons (≳0.5 keV) with duration of minutes sometimes occur in the tail magnetosheath. In this study we used the unique simultaneous measurements from the two Acceleration Reconnection Turbulence and Electrodynamics of Moon's Interaction with the Sun probes to investigate the likely sources, spatial structures, and responsible processes for these hot electron enhancements. The enhancements can be seen at any distance across the magnetosheath, but those closer to the magnetopause are more often accompanied by magnetosheath density and flow magnitudes changing to more magnetosphere-like values. From simultaneous measurements with the two probes being on either side of magnetopause or both in the magnetosheath, it is evident that these hot electrons come from . . .
Date: 12/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020603 Available at: http://doi.wiley.com/10.1002/2014JA020603
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Authors: Jaynes A.N., Baker D.N., Singer H.J., Rodriguez J.V., Loto'aniu T.M., et al.
Title: Source and Seed Populations for Relativistic Electrons: Their Roles in Radiation Belt Changes
Abstract: Strong enhancements of outer Van Allen belt electrons have been shown to have a clear dependence on solar wind speed and on the duration of southward interplanetary magnetic field. However, individual case study analyses also have demonstrated that many geomagnetic storms produce little in the way of outer belt enhancements and, in fact, may produce substantial losses of relativistic electrons. In this study, focused upon a key period in August-September 2014, we use GOES geostationary orbit electron flux data and Van Allen Probes particle and fields data to study the process of radiation belt electron acceleration. One particular interval, 13-22 September, initiated by a short-lived geomagnetic storm and characterized by a long period of primarily northward IMF, showed strong depletion of. . .
Date: 07/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021234 Available at: http://doi.wiley.com/10.1002/2015JA021234
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Authors: Li W, Thorne R M, Bortnik J, Baker D N, Reeves G D, et al.
Title: Solar wind conditions leading to efficient radiation belt electron acceleration: A superposed epoch analysis
Abstract: Determining preferential solar wind conditions leading to efficient radiation belt electron acceleration is crucial for predicting radiation belt electron dynamics. Using Van Allen Probes electron observations (>1 MeV) from 2012 to 2015, we identify a number of efficient and inefficient acceleration events separately to perform a superposed epoch analysis of the corresponding solar wind parameters and geomagnetic indices. By directly comparing efficient and inefficient acceleration events, we clearly show that prolonged southward Bz, high solar wind speed, and low dynamic pressure are critical for electron acceleration to >1 MeV energies in the heart of the outer radiation belt. We also evaluate chorus wave evolution using the superposed epoch analysis for the identified efficient and . . .
Date: 09/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL065342 Available at: http://onlinelibrary.wiley.com/wol1/doi/10.1002/2015GL065342/abstract
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Authors: Thaller S. A., Wygant J R, Cattell C. A., Breneman A. W., Tyler E., et al.
Title: Solar rotation period driven modulations of plasmaspheric density and convective electric field in the inner magnetosphere
Abstract: This paper presents the first analysis of Van Allen Probes measurements of the cold plasma density and electric field in the inner magnetosphere to show that intervals of strong modulation at the solar rotation period occur in the locations of the outer plasmasphere and plasmapause (~0.7 RE peak‐to‐peak), in the large‐scale electric field (~0.24 mV/m peak‐to‐peak), and in the cold plasma density (~250 cm‐3 – ~70 cm‐3 peak‐to‐peak). Solar rotation modulation of the inner magnetosphere is more apparent in the declining phase of the solar cycle than near solar maximum. The periodicities in these parameters are compared to solar EUV irradiance, solar wind dawn‐dusk electric field, and Kp. The variations in the plasmapause location at the solar rotation period anti‐corre. . .
Date: 02/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026365 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026365
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Authors: O'Brien T P, Mazur J E, and Looper M D
Title: Solar Energetic Proton Access to the Magnetosphere During the 10–14 September 2017 Particle Event
Abstract: We explore the penetration of >60 MeV protons into the magnetosphere during the 10–14 September 2017 solar energetic particle event. Solar energetic particles can cause single event effects and total dose degradation in spacecraft electronics. Therefore, it is important for satellite anomaly analysis to understand how deep into the magnetosphere these particles penetrate. Whereas most studies of geomagnetic cutoffs use low‐altitude data, we use data from the Relativistic Proton Spectrometer on National Aeronautics and Space Administration's Van Allen Probes, which is in a high‐altitude, elliptical orbit. We determine how the penetration depends on particle energy, location, and direction of incidence. We evaluate multiple published models of the geomagnetic cutoff to determine how we. . .
Date: 08/2018 Publisher: Space Weather DOI: 10.1029/2018SW001960 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018SW001960
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Authors: Lessard Marc R., Lindgren Erik A., Engebretson Mark J, and Weaver Carol
Title: Solar cycle dependence of ion cyclotron wave frequencies
Abstract: Electromagnetic ion cyclotron (EMIC) waves have been studied for decades, though remain a fundamentally important topic in heliospheric physics. The connection of EMIC waves to the scattering of energetic particles from Earth's radiation belts is one ofmany topics that motivate the need for a deeper understanding of characteristics and occurrence distributions of the waves. In this study, we show that EMIC wave frequencies, as observed at Halley Station in Antarctica from 2008 through 2012, increase by approximately 60% from a minimum in 2009 to the end of 2012. Assuming that these waves are excited in the vicinity of the plasmapause, the change in Kp in going from solar minimum to near solar maximum would drive increased plasmapause erosion, potentially shifting the generation region of t. . .
Date: 04/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020791 Available at: http://doi.wiley.com/10.1002/2014JA020791
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Authors: Meredith Nigel P, Horne Richard B, Glauert Sarah A, and Anderson Roger R
Title: Slot region electron loss timescales due to plasmaspheric hiss and lightning-generated whistlers
Abstract: [1] Energetic electrons (E > 100 keV) in the Earth's radiation belts undergo Doppler-shifted cyclotron resonant interactions with a variety of whistler mode waves leading to pitch angle scattering and subsequent loss to the atmosphere. In this study we assess the relative importance of plasmaspheric hiss and lightning-generated whistlers in the slot region and beyond. Electron loss timescales are determined using the Pitch Angle and energy Diffusion of Ions and Electrons (PADIE) code with global models of the spectral distributions of the wave power based on CRRES observations. Our results show that plasmaspheric hiss propagating at small and intermediate wave normal angles is a significant scattering agent in the slot region and beyond. In contrast, plasmaspheric hiss propagating at large. . .
Date: 08/2007 Publisher: Journal of Geophysical Research DOI: 10.1029/2007JA012413 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2007JA012413/abstract
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Authors: Yuan Zhigang, Yu Xiongdong, Ouyang Zhihai, Yao Fei, Huang Shiyong, et al.
Title: Simultaneous trapping of EMIC and MS waves by background plasmas
Abstract: Electromagnetic ion cyclotron waves and fast magnetosonic waves are found to be simultaneously modulated by background plasma density: both kinds of waves were observed in high plasma density regions but vanished in low density regions. Theoretical analysis based on Snell's law and linear growth theory have been utilized to investigate the physical mechanisms driving such modulation. It is suggested that the modulation of fast magnetosonic waves might be due to trapping by plasma density structures, which results from a conservation of the parameter Q during their propagation. Here Q = nrsinψ, with n the refractive index, r the radial distance, and ψ the wave azimuthal angle. As for electromagnetic ion cyclotron waves, the modulation might be owed to the ion composition difference betwee. . .
Date: 02/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026149 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026149
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Authors: Chiu Y T, Nightingale R W, and Rinaldi M A
Title: Simultaneous Radial and Pitch Angle Diffusion in the Outer Electron Radiation Belt
Abstract: A solution of the bimodal (radial and pitch angle) diffusion equation for the radiation belts is developed with special regard for the requirements of satellite radiation belt data analysis. In this paper, we use this solution to test the bimodal theory of outer electron belt diffusion by confronting it with satellite data. Satellite observations, usually over finite volumes of (L, t) space, are seldom sufficient in space-time duration to cover the relaxation to equilibrium of the entire radiation belt. Since time scales of continuous data coverage are often comparable to that of radiation belt disturbances, it is therefore inappropriate to apply impulsive semi-infinite time response solutions of diffusion theory to interpret data from a finite window of (L, t) space. Observational limitat. . .
Date: 04/1988 Publisher: Journal of Geophysical Research Pages: 2619 - 2632 DOI: 10.1029/JA093iA04p02619 Available at: http://onlinelibrary.wiley.com/doi/10.1029/JA093iA04p02619/abstract
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Authors: Ghamry E., Kim K.-H., Kwon H.-J., Lee D.-H., Park J.-S., et al.
Title: Simultaneous Pi2 observations by the Van Allen Probes inside and outside the plasmasphere
Abstract: Plasmaspheric virtual resonance (PVR) model has been proposed as one of source mechanisms for low-latitude Pi2 pulsations. Since PVR-associated Pi2 pulsations are not localized inside the plasmasphere, simultaneous multipoint observations inside and outside the plasmasphere require to test the PVR model. Until now, however, there are few studies using simultaneous multisatellite observations inside and outside the plasmasphere for understanding the radial structure of Pi2 pulsation. In this study, we focus on the Pi2 event observed at low-latitude Bohyun (BOH, L = 1.35) ground station in South Korea in the postmidnight sector (magnetic local time (MLT) = 3.0) for the interval from 1730 to 1900 UT on 12 March 2013. By using electron density derived from the frequency of the upper hybrid wav. . .
Date: 05/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021095 Available at: http://doi.wiley.com/10.1002/2015JA021095
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Authors: Mozer F S, Agapitov O. V., Blake J B, and Vasko I. Y.
Title: SIMULTANEOUS OBSERVATIONS OF LOWER BAND CHORUS EMISSIONS AT THE EQUATOR AND MICROBURST PRECIPITATING ELECTRONS IN THE IONOSPHERE
Abstract: On December 11, 2016 at 00:12:30 UT, Van Allen Probe-B, at the equator and near midnight, and AC6-B, in the ionosphere, were on magnetic field lines whose 100 km altitude foot points were separated by 600 km. Van Allen Probe-B observed a 30 second burst of lower band chorus waves (with maximum amplitudes >1 nT) at the same time that AC6-B observed intense microburst electrons in the loss cone. One-second averaged variations of the chorus intensity and the microburst electron flux were well-correlated. The low altitude electron flux expected from quasi-linear diffusion of the equatorial electrons by the equatorial chorus is in excellent agreement with the observed, one second averaged, low altitude electron flux. However the large amplitude, <0.5 second duration, low altitude electron pulse. . .
Date: 12/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL076120 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL076120/full
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Authors: Schiller Q., Tu W., Ali A. F., Li X, Godinez H. C., et al.
Title: Simultaneous event-specific estimates of transport, loss, and source rates for relativistic outer radiation belt electrons
Abstract: The most significant unknown regarding relativistic electrons in Earth's outer Van Allen radiation belt is the relative contribution of loss, transport, and acceleration processes within the inner magnetosphere. Detangling each individual process is critical to improve the understanding of radiation belt dynamics, but determining a single component is challenging due to sparse measurements in diverse spatial and temporal regimes. However, there are currently an unprecedented number of spacecraft taking measurements that sample different regions of the inner magnetosphere. With the increasing number of varied observational platforms, system dynamics can begin to be unraveled. In this work, we employ in situ measurements during the 13–14 January 2013 enhancement event to isolate transport,. . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023093 Available at: http://doi.wiley.com/10.1002/2016JA023093
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Title: Simultaneous disappearances of plasmaspheric hiss, exohiss, and chorus waves triggered by a sudden decrease in solar wind dynamic pressure
Abstract: Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. Here on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration with the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappea. . .
Date: 01/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL071987 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL071987
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Authors: Liu Nigang, Su Zhenpeng, Gao Zhonglei, Zheng Huinan, Wang Yuming, et al.
Title: Simultaneous disappearances of plasmaspheric hiss, exohiss, and chorus waves triggered by a sudden decrease in solar wind dynamic pressure
Abstract: Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. Here on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration with the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappea. . .
Date: 01/2017 Publisher: Geophysical Research Letters Pages: 52 - 61 DOI: 10.1002/2016GL071987 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL071987/full
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Authors: De Pascuale S., Jordanova V K, Goldstein J, Kletzing C A, Kurth W S, et al.
Title: Simulations of Van Allen Probes Plasmaspheric Electron Density Observations
Abstract: We simulate equatorial plasmaspheric electron densities using a physics‐based model (Cold PLasma, CPL; used in the ring current‐atmosphere interactions model) of the source and loss processes of refilling and erosion driven by empirical inputs. The performance of CPL is evaluated against in situ measurements by the Van Allen Probes (Radiation Belt Storm Probes) for two events: the 31 May to 5 June and 15 to 20 January 2013 geomagnetic storms observed in the premidnight and postmidnight magnetic local time (MLT) sectors, respectively. Overall, CPL reproduces the radial extent of the plasmasphere to within a mean absolute difference of urn:x-wiley:jgra:media:jgra54637:jgra54637-math-0001 L. The model electric field responsible for E × B convection and the parameterization of geomagn. . .
Date: 11/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025776 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025776
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Authors: Jordanova V K, Yu Y., Niehof J T, Skoug R M, Reeves G D, et al.
Title: Simulations of inner magnetosphere dynamics with an expanded RAM-SCB model and comparisons with Van Allen Probes observations
Abstract: Simulations from our newly expanded ring current-atmosphere interactions model with self-consistent magnetic field (RAM-SCB), now valid out to 9 RE, are compared for the first time with Van Allen Probes observations. The expanded model reproduces the storm time ring current buildup due to the increased convection and inflow of plasma from the magnetotail. It matches Magnetic Electron Ion Spectrometer (MagEIS) observations of the trapped high-energy (>50 keV) ion flux; however, it underestimates the low-energy (<10 keV) Helium, Oxygen, Proton, and Electron (HOPE) observations. The dispersed injections of ring current ions observed with the Energetic particle, Composition, and Thermal plasma (ECT) suite at high (>20 keV) energy are better reproduced using a high-resolution convection model. . . .
Date: 04/2014 Publisher: Geophysical Research Letters Pages: 2687 - 2694 DOI: 10.1002/2014GL059533 Available at: http://doi.wiley.com/10.1002/2014GL059533
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Authors: Eshetu W. W., Lyon J G, Hudson M K, and Wiltberger M. J.
Title: Simulations of Electron Energization and Injection by BBFs Using High-Resolution LFM MHD Fields
Abstract: We study electron injection and energization by bursty bulk flows (BBFs), by tracing electron trajectories using magnetohydrodynamic (MHD) field output from the Lyon‐Fedder‐Mobarry (LFM) code. The LFM MHD simulations were performed using idealized solar wind conditions to produce BBFs. We show that BBFs can inject energetic electrons of few to 100 keV from the magnetotatail beyond −24 RE to inward of geosynchronous, while accelerating them in the process. We also show the dependence of energization and injection on the initial relative position of the electrons to the magnetic field structure of the BBF, the initial pitch angle, and the initial energy. In addition, we have shown that the process can be nonadiabatic with violation of the first adiabatic invariant (μ). Further, we d. . .
Date: 02/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025789 Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JA025789
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Authors: Goldstein J, De Pascuale S., Kletzing C., Kurth W., Genestreti K. J., et al.
Title: Simulation of Van Allen Probes Plasmapause Encounters
Abstract: We use an E × B-driven plasmapause test particle (PTP) simulation to provide global contextual information for in situ measurements by the Van Allen Probes (RBSP) during 15–20 January 2013. During 120 h of simulation time beginning on 15 January, geomagnetic activity produced three plumes. The third and largest simulated plume formed during enhanced convection on 17 January, and survived as a rotating, wrapped, residual plume for tens of hours. To validate the simulation, we compare its output with RBSP data. Virtual RBSP satellites recorded 28 virtual plasmapause encounters during 15–19 January. For 26 of 28 (92%) virtual crossings, there were corresponding actual RBSP encounters with plasmapause density gradients. The mean difference in encounter time between model and data is. . .
Date: 09/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020252 Available at: http://doi.wiley.com/10.1002/2014JA020252
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Authors: Brito T, Hudson M K, Kress B., Paral J., Halford A., et al.
Title: Simulation of ULF wave modulated radiation belt electron precipitation during the 17 March 2013 storm
Abstract: Balloon-borne instruments detecting radiation belt precipitation frequently observe oscillations in the mHz frequency range. Balloons measuring electron precipitation near the poles in the 100 keV to 2.5 MeV energy range, including the MAXIS, MINIS, and most recently the BARREL balloon experiments, have observed this modulation at ULF wave frequencies [e.g. Foat et al., 1998; Millan et al., 2002; Millan, 2011]. Although ULF waves in the magnetosphere are seldom directly linked to increases in electron precipitation since their oscillation periods are much larger than the gyroperiod and the bounce period of radiation belt electrons, test particle simulations show that this interaction is possible [Brito et al., 2012]. 3D simulations of radiation belt electrons were performed to investigate . . .
Date: 03/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020838 Available at: http://doi.wiley.com/10.1002/2014JA020838
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Authors: Li Xinlin, Roth I, Temerin M, Wygant J R, Hudson M K, et al.
Title: Simulation of the prompt energization and transport of radiation belt particles during the March 24, 1991 SSC
Abstract: We model the rapid (∼ 1 min) formation of a new electron radiation belt at L ≃ 2.5 that resulted from the Storm Sudden Commencement (SSC) of March 24, 1991 as observed by the CRRES satellite. Guided by the observed electric and magnetic fields, we represent the time-dependent magnetospheric electric field during the SSC by an asymmetric bipolar pulse that is associated with the compression and relaxation of the Earth's magnetic field. We follow the electrons using a relativistic guiding center code. The test-particle simulations show that electrons with energies of a few MeV at L > 6 were energized up to 40 MeV and transported to L ≃ 2.5 during a fraction of their drift period. The energization process conserves the first adiabatic invariant and is enhanced due to resonance of the el. . .
Date: 11/1993 Publisher: Geophysical Research Letters Pages: 2423–2426 DOI: 10.1029/93GL02701 Available at: http://onlinelibrary.wiley.com/doi/10.1029/93GL02701/abstract
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Authors: Desorgher L, ühler P, Zehnder A, and ückiger E O
Title: Simulation of the outer radiation belt electron flux decrease during the March 26, 1995, magnetic storm
Abstract: In this paper we study the variation of the relativistic electron fluxes in the Earth's outer radiation belt during the March 26, 1995, magnetic storm. Using observations by the radiation environment monitor (REM) on board the space technology research vehicle (STRV-Ib), we discuss the flux decrease and possible loss of relativistic electrons during the storm main phase. In order to explain the observations we have performed fully adiabatic and guiding center simulations for relativistic equatorial electrons in the nonstationary Tsygarienko96 magnetospheric magnetic field model. In our simulations the drift of electrons through the magnetopause was considered as a loss process. We present our model results and discuss their dependence on the magnetospheric magnetic and electric field model. . .
Date: 09/2000 Publisher: Journal of Geophysical Research Pages: 21211 DOI: 10.1029/2000JA900060 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2000JA900060/full
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Authors: Patel Maulik, Li Zhao, Hudson Mary, Claudepierre Seth, and Wygant John
Title: Simulation of Prompt Acceleration of Radiation Belt Electrons During the 16 July 2017 Storm
Abstract: We investigate the prompt enhancement of radiation belt electron flux observed by the Relativistic Electron Proton Telescope instrument on board Van Allen Probes following the 16 July 2017 CME‐shock compression using MHD‐test particle simulations. The prompt enhancements can be explained by the source population interacting with the azimuthally directed electric field impulses induced by CME‐shock compressions of the dayside magnetopause. Electrons in drift resonance with the electric field impulse were accelerated by ∼ 0.6 MeV on a drift period timescale (in minutes) as the impulse propagated from the dayside to the nightside around the flanks of the magnetosphere. MHD test particle simulation of energization and drift phase bunching, due to the bipolar electric field that accompa. . .
Date: 06/2019 Publisher: Geophysical Research Letters DOI: 10.1029/2019GL083257 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083257
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Authors: Pakhotin I. P., Drozdov A. Y., Shprits Y Y, Boynton R. J., Subbotin D. A., et al.
Title: Simulation of high-energy radiation belt electron fluxes using NARMAX-VERB coupled codes
Abstract: This study presents a fusion of data-driven and physics-driven methodologies of energetic electron flux forecasting in the outer radiation belt. Data-driven NARMAX (Nonlinear AutoRegressive Moving Averages with eXogenous inputs) model predictions for geosynchronous orbit fluxes have been used as an outer boundary condition to drive the physics-based Versatile Electron Radiation Belt (VERB) code, to simulate energetic electron fluxes in the outer radiation belt environment. The coupled system has been tested for three extended time periods totalling several weeks of observations. The time periods involved periods of quiet, moderate, and strong geomagnetic activity and captured a range of dynamics typical of the radiation belts. The model has successfully simulated energetic electron fluxes . . .
Date: 10/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020238 Available at: http://doi.wiley.com/10.1002/2014JA020238
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Authors: Ma Q, Li W, Thorne R M, Nishimura Y., Zhang X.-J., et al.
Title: Simulation of energy-dependent electron diffusion processes in the Earth's outer radiation belt
Abstract: The radial and local diffusion processes induced by various plasma waves govern the highly energetic electron dynamics in the Earth's radiation belts, causing distinct characteristics in electron distributions at various energies. In this study, we present our simulation results of the energetic electron evolution during a geomagnetic storm using the University of California, Los Angeles 3-D diffusion code. Following the plasma sheet electron injections, the electrons at different energy bands detected by the Magnetic Electron Ion Spectrometer (MagEIS) and Relativistic Electron Proton Telescope (REPT) instruments on board the Van Allen Probes exhibit a rapid enhancement followed by a slow diffusive movement in differential energy fluxes, and the radial extent to which electrons can penetra. . .
Date: 05/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022507 Available at: http://doi.wiley.com/10.1002/2016JA022507
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Authors: Glauert Sarah A, Horne Richard B, and Meredith Nigel P
Title: Simulating the Earth's radiation belts: Internal acceleration and continuous losses to the magnetopause
Abstract: In the Earth's radiation belts the flux of relativistic electrons is highly variable, sometimes changing by orders of magnitude within a few hours. Since energetic electrons can damage satellites it is important to understand the processes driving these changes and, ultimately, to develop forecasts of the energetic electron population. One approach is to use three-dimensional diffusion models, based on a Fokker-Planck equation. Here we describe a model where the phase-space density is set to zero at the outer L∗ boundary, simulating losses to the magnetopause, using recently published chorus diffusion coefficients for 1.5≤L∗≤10. The value of the phase-space density on the minimum-energy boundary is determined from a recently published, solar wind-dependent, statistical model. Our s. . .
Date: 09/2014 Publisher: Journal of Geophysical Research: Space Physics Pages: 7444 - 7463 DOI: 10.1002/jgra.v119.910.1002/2014JA020092 Available at: http://doi.wiley.com/10.1002/jgra.v119.9http://doi.wiley.com/10.1002/2014JA020092
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Authors: Sarris T, Li X, and Temerin M
Title: Simulating radial diffusion of energetic (MeV) electrons through a model of fluctuating electric and magnetic fields
Abstract: In the present work, a test particle simulation is performed in a model of analytic Ultra Low Frequency, ULF, perturbations in the electric and magnetic fields of the Earth's magnetosphere. The goal of this work is to examine if the radial transport of energetic particles in quiet-time ULF magnetospheric perturbations of various azimuthal mode numbers can be described as a diffusive process and be approximated by theoretically derived radial diffusion coefficients. In the model realistic compressional electromagnetic field perturbations are constructed by a superposition of a large number of propagating electric and consistent magnetic pulses. The diffusion rates of the electrons under the effect of the fluctuating fields are calculated numerically through the test-particle simulation as a. . .
Date: 10/2006 Publisher: Annales Geophysicae Pages: 2583 - 2598 DOI: 10.5194/angeo-24-2583-2006 Available at: http://www.ann-geophys.net/24/2583/2006/angeo-24-2583-2006.html
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Authors: Hudson Mary, Jaynes Allison, Kress Brian, Li Zhao, Patel Maulik, et al.
Title: Simulated prompt acceleration of multi-MeV electrons by the 17 March 2015 interplanetary shock
Abstract: Prompt enhancement of relativistic electron flux at L = 3−5 has been reported from Van Allen Probes Relativistic Electron Proton Telescope (REPT) measurements associated with the 17 March 2015 interplanetary shock compression of the dayside magnetosphere. Acceleration by ∼ 1 MeV is inferred on less than a drift time scale as seen in prior shock compression events, which launch a magetosonic azimuthal electric field impulse tailward. This impulse propagates from the dayside around the flanks accelerating electrons in drift resonance at the dusk flank. Such longitudinally localized acceleration events produce a drift echo signature which was seen at >1 MeV energy on both Van Allen Probe spacecraft, with sustained observations by Probe B outbound at L = 5 at 2100 MLT at the time of impuls. . .
Date: 09/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024445 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024445/full
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Authors: Hudson M K, Baker D N, Goldstein J, Kress B T, Paral J., et al.
Title: Simulated magnetopause losses and Van Allen Probe flux dropouts
Abstract: Three radiation belt flux dropout events seen by the Relativistic Electron Proton Telescope soon after launch of the Van Allen Probes in 2012 (Baker et al., 2013a) have been simulated using the Lyon-Fedder-Mobarry MHD code coupled to the Rice Convection Model, driven by measured upstream solar wind parameters. MHD results show inward motion of the magnetopause for each event, along with enhanced ULF wave power affecting radial transport. Test particle simulations of electron response on 8 October, prior to the strong flux enhancement on 9 October, provide evidence for loss due to magnetopause shadowing, both in energy and pitch angle dependence. Severe plasmapause erosion occurred during ~ 14 h of strongly southward interplanetary magnetic field Bz beginning 8 October coincident with. . .
Date: 02/2014 Publisher: Geophysical Research Letters Pages: 1113 - 1118 DOI: 10.1002/2014GL059222 Available at: http://doi.wiley.com/10.1002/2014GL059222
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Authors: Aseev N. A., Shprits Y Y, Drozdov A. Y., Kellerman A. C., Usanova M. E., et al.
Title: Signatures of Ultrarelativistic Electron Loss in the Heart of the Outer Radiation Belt Measured by Van Allen Probes
Abstract: Up until recently, signatures of the ultrarelativistic electron loss driven by electromagnetic ion cyclotron (EMIC) waves in the Earth's outer radiation belt have been limited to direct or indirect measurements of electron precipitation or the narrowing of normalized pitch angle distributions in the heart of the belt. In this study, we demonstrate additional observational evidence of ultrarelativistic electron loss that can be driven by resonant interaction with EMIC waves. We analyzed the profiles derived from Van Allen Probe particle data as a function of time and three adiabatic invariants between 9 October and 29 November 2012. New local minimums in the profiles are accompanied by the narrowing of normalized pitch angle distributions and ground-based detection of EMIC waves. Such a cor. . .
Date: 09/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024485 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024485/full
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Authors: Lejosne Solène, and Mozer F S
Title: Shorting Factor In‐Flight Calibration for the Van Allen Probes DC Electric Field Measurements in the Earth's Plasmasphere
Abstract: Satellite‐based direct electric field measurements deliver crucial information for space science studies. Yet they require meticulous design and calibration. In‐flight calibration of double‐probe instruments is usually presented in the most common case of tenuous plasmas, where the presence of an electrostatic structure surrounding the charged spacecraft alters the geophysical electric field measurements. To account for this effect and the uncertainty in the boom length, the measured electric field is multiplied by a parameter called the shorting factor (sf). In the plasmasphere, the Debye length is very small in comparison with spacecraft dimension, and there is no shorting of the electric field measurements (sf = 1). However, the electric field induced by spacecraft motion greatly . . .
Date: 04/2019 Publisher: Earth and Space Science Pages: 646 - 654 DOI: 10.1029/2018EA000550 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018EA000550
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